Heretofore, the amount of magnetic material such as ferrite generally incorporated into a composition has been limited by the type of binder utilized. For example, U.S. Pat. No. 3,124,725 to Leguillon relates to a flexible plastic permanent magnet having a body portion and a relatively thin elastic high skin strength cover which is highly resistant to cracking so that the plastic permanent magnet as a whole is highly resistant to cracking in service.
U.S. Pat. No. 3,282,909 to Manuel et al relates to metal carbonyl polymer complexes which can be blended with conventional synthetic rubbers and heat-treated or vulcanized in the presence of a strong magnetic field thereby enhancing the magnetic properties of the resulting polymer.
U.S. Pat. No. 3,933,536 to Doser et al relates to magnets which are produced by dissolving an organic polymer in a solvent, adding a magnetic powder to the solution, and then adding the solution to a vehicle in which the polymer is insoluble.
U.S. Pat. No. 3,956,440 to Deschamps et al relates to the production of fine grained ferrite bodies utilizing a process for the production of ferrimagnetic materials obtained by coprecipitation from a stoichiometric mixture of metallic salts corresponding to the material composition by means of a base comprising an isostatic pressing step of the dried oxides followed by a short vacuum heat treatment of complete duration under 12 hours.
U.S. Pat. No. 4,190,548 to Baermann relates to a plastic bonded permanent magnet having magnet particles which have a high affinity for oxygen such as ultra-fine grain iron, bismuth-manganese and cobalt rare earth magnetic materials, dispersed within a substantially oxygen-free plastic.
U.S. Pat. No. 4,200,547 to Beck relates to a matrix-bonded permanent magnet comprising anisotropic magnetic particles which have an alignment exceeding 90 percent. The binder is a mixture of an amorphous hot-melt polyamide resin and a processing additive which is a cyclic nitrile derivative of a saturated fatty acid dimer.
U.S. Pat. No. 4,292,261 to Kotani et al relates to a pressure sensitive conductor and method of manufacturing the same wherein the conductor comprises an elastomer containing from 3 to 40 percent by volume of conductive magnetic particles.
U.S. Pat. No. 4,496,303 to Loubler relates to a method of fabricating a permanent magnet wherein a plastic bonded magnet is formed of a solidified mixture of a thermoplastic powder and magnetic particles capable of being permanently magnetized.
U.S. Pat. No. 4,689,163 to Yamashita, et al relates to a resin-bonded magnet comprising particles of a melt-quenched ferromagnetic material and a binder having at least an alcoholic hydroxyl group and a block isocyanate with an active hydrogen-bearing compound.